Telephone-exchange system



April 8, 1930. A. E. HAGUE ET AL 1,753,338

' 4 TELEPHONE EXCHANGE SYSTEM Filed May 9. 1928 OFAIVOTHE ALFRED E #4505 55mm: l1 FETmsa/v A TTORNE) subscriber.

Patented Apr. 8, 1930 STATES PATENT 0pm:

ALFRED n. HAGUE, on vrnsr ORANGE, AND GEORGE H. rnrnnson, on BLooMriIELn,

NEW JERSEY, ASSIGNORS TO BELL TELEPHONE LABORATORIES, INCORPORATED, OF

NEW YORK, N. Y., A CORPOBATIQN OF NEW YORK TELEPHONE-EXGfiANGE SYSTEM Application filed May 9, 1928. Serial No. 276,243.

This invention relates to telephone ex change systems, and more particularly to such systems wherein iink circuits are employed in the establishment of telephone connections.

in such systems it is desirable to provide means whereby an attending operator may be informed that the period, of conversation be-.

tween subscribers stations on interconnected lines has reached a definite allotted time, so that overtime charges may be'recorded for time consumed in excess of the allotted period.

It is the object ofthis invention to transmit to an operator supervising a connection between subscribers lines, a distinctive signal upon the expiration of a predetermined period of time after the response of a called T his object is attained in accordance with a feature of the invention by the provision of timing equipment which comprises a plurality of cooperating selector switches associated with an operators cord circuit, which are controlled by a calling supervisory relay in the cord'circuit and function to cause the flashing of the answering andcalling supervisorylamps after a predetermined period of time-has elapsed since the response of a called subscriber.

Another feature of the invention resides in the provision of means whereby an untimely operation of the supervisory relay in the'op-- erators cord circuit does not cause the timing equipment to function to transmit a false signal to the attending operator.

This second feature is accomplished by delaying the locking of the selector control relay until the selector individual to thecord circuit has advanced a predetermined number of positions. In this manner the premature accompanying drawing which discloses a callstations.

ing isubscriberls Station. it called sub? scribers station B and an operators cord circuit C with associated timing equipment, which is employed to interconnect the two The timing equipment comprises a plurality of power driven selector switches or multi-positionswitches of the well known type and it is believed a description of their mechanical. design and operating circuits is unnecessary. The selector switches are 00-.

call, removes the receiver from the switch-1, hook and in so doing causes relay 5 to operate in an obvious circuit. 7 Relay 5 in operating causes the line lamp 6 to be lighted as a signal to an operator at the central oflice that a call on line 7 is awaiting attention. An operator at the central office proceeds to answer the call by inserting plug 8 of the cord circuit G located at her position, intojack 9 associated with the lighted line-lamp 6, and

actuating the talking key 10.

' The actuation of talking key 10 connects the operators telephone set (not shown), but indicated at OT, with the talking leads of the cord circuit C. At contact 12 of the talking keyan obvious circuit is prepared for relay 13, which relay thereupon operates.

The insertion of plug 8 into jack 9 establishes a circuit which may be traced from grounded battery, outer left hand armature and front contact of relay 13, the No. 1 terminal of are T of selector switch .T, switch arm 16, resistance elements 15 and 14, sleeve contacts of plug 8 and'jack 9, winding of sleeve relay 17 to ground. Relay 1'? operates in this circuit, opening the circuit for line relay 5 which releases, causing line lamp 6 to be extinguished. The resistanceelement 15 is relatively low and shunts the answering supervisory lamp 18 preventing it from lighting at this time. Relay 20 now operates in a front contact and armature of relay 20, in

n'er left hand armature and front contact of relay 13, winding of relay 13 to ground. Helay 13 is now held operated under the control of the calling subscriber.

When the operators telephone set is associated with the cord circuit C, the operator inquires of the calling subscriber the nature of the desired connection, and upon learning that the subscriber at station B associated with line 22 is desired, she proceeds to set up the connection by testing the jack 23 associated with line 22 in the usual well known manner, and finding the line idle inserts the calling plug 24 of the cord circuit G into ]ack The insertion of plug 24 into jack 23 establishes a circuit extending from grounded battery, filament of lamp 25, resistance element 26, No. 1 terminal of switch are T, switch arm 23, sleeve contacts of plug 24 and jack 23, winding of sleeve rela 28 to ground. Relay 28 operates in this circuit and opens the circuit for line relay 29 to prevent its operation and the subsequent lighting of line lamp 30. The lamp 25 is lighted in the circuit just traced.

The operator now actuates ringing key 31 which removes the short circuits from condensers 32 and 33 and connects the ringing current source 34 to the called line. The removal of the short circuits from the condensers 32 and33 effects a path for the ringing current back to the answering end of the cord circuit C and to the calling subscribers station A, so that the calling subscriber may hear the ringing signal. The signaling equipment at station B is actuated by current from the source 34. The operator then restores the ringing key 31, removing the source 34 from the connection and again short circuit-- ing the condensers 32 and 33.

When the called subscriber at station B removes the receiver from the switchhook in answer to the ringing signal, acircuit is established extending from grounded battery, lower right hand winding of repeating coil '21, winding of relay 35, lower normal conconnection.

circuit extending from grounded battery, armature and front contact of relay 35, switch arm 37 of arc T conductor 38 to ground, through the left hand winding of relay 36.

Relay 36, in operating as described, establishes an obvious circuit for relay 42 by way of its inner left hand armature and front contact. At its outer left hand armature and front contact a circuit is established extending from grounded battery, winding of step magnet 43, outer left hand armature and front contact of relay 36, switch arm 44 and terminal No. 1 of arc T terminal No. 1 and switch arm 45 of arc T back contact and armature of magnet 43 to ground. At its right hand armature and front contact, re-

lay 36 prepares a locking circuit for itself which is completed when the selector T is advanced to position No. 3, as Wlll be described directly. The selector T advances from posi-? tion 2 to position 20 under control of the selector D, as Wlll appear from a later description.

W hen selector T reaches position #2, battery associated with terminal #2 of arc T shunts the lamp 25 causing it to be extinguished. When the selector T reaches position #3 a circuit is established in which the resistance element 40 is connected in parallel with lamp 25, causing the lamp to remain eX- reaches position 3, the locking circuit origi-" nally prepared by the operation of relay 36 is completed, and may be traced from grounded battery, filament of lamp 25, right hand winding of relay 36, righthand armature and front contact of relay 36, terminals 3 to 22 and switch arm 27 of are T to ground on the sleeve Lamp 25 is still connected in parallel with resistance element 40 by way of are T and the front contact and armature of relay 35 and accordingly does not receive sufficient current to be lighted at this time.

The purpose for completing the locking circuit for relay 36 only after the selector T has passed through. the first two positions is to prevent the premature locking of the timing equipment should supervisory relay 35 be actuated accidentally. Relay 35 being connected in the cord circuit may receive a momentary kick or impulse due to the association of the calling end of cord circuit C with connecting links in which bridge circuits may be encountered, such as trunk circuits. A tripping bridge across a trunk circuit with which the cord circuit C may be associated or a surge following the plugging in of the cord ice to a link circuit would momentarily establish an operating circuit for relay 35, which in functioning causes relay 36 to operate and start the timing equipment to be set in motion. The timing equipment would then continue operating and would cause the transmission of a false signal to the operator and the calling subscriber would be chargedffor time in excess of the period actually consumed in conversation. By delaying the completion of the locking circuit for relay 36 until selector T has reached position No. 3, relay if accidentally actuated, has time to restoreand open the energizing circuit for relay 36 before the latter is locked in the sleeve circuit. The release of relay 35, followingsuch a premature operation, releases relay 36, which returns the selector T to normal under the control of arc T The feature'of'delaying the locking in of the timing equipment until a certain interval of time has elapsed since the actuation of re, lay 35, insures against the premature transmission of an overtime signal to the operator and the-consequent overcharging of the subscriber.

The object in having relay 36 lock under the control of the plug sleeve isto insure its release and consequently the resetting of the timing equipment in case the operator withdraws plug 24 from a connection and reinserts it in another jackas she would do when attempting to call a new number.

Relay 46 is controlled by a clock mechanism schematically representedatfW and isoperated at regular intervals upon eachv closure of the clock circuit. The clock mechanism indicated at W may be of any'well known type. With relay 42 operated as hereinbefore described, relay follows the operations of the clock controlled relay T6; and accordingly causes the step magnet 48 to step the selector E around one position for each operation of relay 16. It is therefore observed that the selector E is directly controlled by the clock mechanism V]. For practical'purposes the clock mechanism is regulated to close the cir- 011113 for relay a6 once every SIX seconds and the selector E is accordingly advanced one position for the elapse of every like period of time.

At every third step of selector-E, that is, every eighteen seconds, relay 4%) is operated in a circuit extending from groundedbattery, winding of relay 49, every third terminal of are E of selector E, switch arm 50 to ground at the outer armature and front contact of,

' tionto position No. 2. It will be noted, that of are D switch arm to grounded battery through the winding of relay 52.

It will now be noted that the terminals of arc D of selector D are distributedamong a numberof cord circuits, such as the cord circuit O, and that-one terminal is assigned: to each particular cord. In thev drawing, the

"eighteenth terminal 59 has been assumed to be allotted to the cord circuit C, and this terminal is tied to the terminals of arc T of selector T which is individual'to the cord circuit Therefore, for every revolution of the selector D, the terminal 59 of arc D receives ground from the switch arm 60, whereupon step magnet 43 of selector T is energized. Thls energizing circuit may be traced from grounded battery, winding of magnet 43, outer left hand armature and front contactof relay 36, switch armed, terminals of are T of selector-T,terminal 59 of arm D of selector D to ground, on the switch arm 60.- Itwill therefore be observed that for every complete revolution of selector D, the vanced one position. I As long as relay 42 remains operated,=se-

selector T is ad- I lector E continues to function and every time the terminals 61, .62 and every third terminal thereafter of arc E is engaged by switch arm 50, the selector D is caused to make one revolution as already described.

When selector'T reaches position 20 under the control of selector D, the lamps 18 and 25 are flashed in a; characteristic manner as follows: The twentieth terminal on the arcs T and T are joined together by the conductor 63, so that when switch arm 64L-reaches the terminal or are T and switch arm 16 reaches a corresponding terminal of are T", the lamps 18 and 25 will be connected in parallel to the twentieth terminal of are T which'is associated with the-low resistance left hand winding of relay 66. Accordingly with the lamps 18 and 25 now connected in parallel and the low resistance left hand winding of relay 66 includedjn the circuit, the lamps receive suflicient current to be lighted, and relay 66 to be operated. Upon the operation of relay 66, the interrupter-67 is placed in circuit with relay 68, sothat this relay operates'when the interrupter brush engages a conducting segment, and causes the audible signalTO'to function. At its left hand armature relay 68 causes relay 66 to lock in an obvious circuit and at the same time opens the circuit to the lamps 18 and 25, whereupon these lamps are extinguished.

'When the brush of interrupter 67 engages the next insulating segment, the operating circuit for relay 68 is opened and this relay restores, silencing the audible signal and again connecting lamps 18 and 25 in circuit with the low resistance, left hand winding of relay 66. These lamps accordingly are again lighted. The next conducting segment encountered by the brush of interrupter 67 reactuates relay 68 to again cause the audible signal 70 to be sounded and the lamps 18 and 25 to be extinguished. In this manner thesupervisory lamps 18 and 25 are caused to flash and the audible signal to be actuated intermittently as long as the selector D is in its twentieth position.

Upon receipt of such a signal the operator tallies overtime in any suitable manner so to charge the calling subscriber in accordance with the time consumed in conversation. The operator then actuates key and immediately releases it. Relay 76 is accordingly operated and places ground on the twentieth terminal of are T of selector T, whereupon step magnet 43 is actuated in a circuit extending from grounded battery, winding of magnet 13, outer left hand armature and front contact of relay 36, switch arm 44 and twentieth terminal of are T to ground on the armature and frontcontact of relay 76. The step magnet thereupon advances selector T to position 21 and at this point it is advanced to normal position under the control of are T by way of the back contact of step magnet 13. This circuit is obvious.

If the subscribers continue to converse after the transmission of an overtime signal, the switches continue to function in the same cycle of operations, as just described and for every complete revolution of selector T, the lamps 18 and 25 flash and the audible signal 70 is sounded to indicate to the operator to record overtime.

At the termination of conversation the calling and called subscribers replace their receivers on the switchooks, whereupon relays 20, 35 and 13 are released. The release of relays 20 and 35 causes the resistance elements 15 and 40 to be removed from the circuits of lamps 18 and 25, respectively, whereupon these lamps are lighted steadily over the sleeve circuits as a disconnect signal. The operator thereupon proceeds to take down the connection by withdrawing the answering and calling plugs from jacks 9 and 23 respectively. The removal of the calling cord from ack 23 effects the release of relays 36 and 42. If at this time the selector T is off terminal No. 1, which is its normal position, it is advanced to normal under control of arc T The circuit for step magnet 43 under this condition is believed to be obvious.

'l/Vhen relay 4E2 releases, the circuit for relay 47 is opened and ground is removed from selector E at are E which causes the release of relay 49 if operated at this time. If selector E is off normal at this time, it is advanced to normal under control of are E and the circuit is restored to normal.

From the foregoing description it is evident that the selectors E, D and T cooperate to effect the transmission of an overtime signal to the supervising operator and that the answering and calling supervisory lamps are flashed simultaneously. The selector E is directly controlled by the clock mechanism indicated at W and is so arranged that the ofliceload is distributed equally. The terminals of are E are so interconnected that the entire oflice load is divided into three groups and every third terminal of are E serves the same group of cord circuits. For every operators position there is assigned one arc, such as are D of selector D, each cord of the same position being allotted one terminal, such as 59, on the same are such as D Other arcs, such as D of selector D are assigned to other operators positions. The selector D therefore serves a plurality of positions at the exchange, each are thereof being assigned to one position, whereas each cord circuit, such as cord C, has a se lector T individually allotted thereto.

lVhat is claimed is:

1. In a telephone exchange system, a plurality of lines terminating at a central office. a pin ality of link circuits thereat for inter connecting said lines, signaling devices for said link circuits, a plurality of selector switches for actuating said signaling devices, and means controlled jointly by the operator and the subscriber on a connected line for actuating said selector switches to effect the operation of said signaling devices a predetermined period of time after the response of a subscriber toa connection between said lines.

2. In a telephone exchange system, a plurality of lines terminating at a central office, a plurality of link circuits thereat for interconnecting said lines, signaling devices for said link circuits, a selector switch for each of said link circuits for actuating said signaling devices upon the arrival of said switch at a predetermined position thereof, and time regulated means for advancing said selector switch to said predetermined position.

3. In a telephone exchange system, a plurality of lines terminating at a central oflice, a plurality of link circuits thereat for interconnecting said lines. signaling devices for said link circuits, a selector switch for each of said link circuits for actuating said signaling devices upon the arrival of said switch at a predetermined position thereof, and a plurality of time regulated selector switches common to said plurality of link circuitsfor advancing said first selector switch to said predetermined position. I I j 4. In a telephone exchange system, a plurality of lines terminating at a central oflice, a plurality of link circuits thereat for interconnecting said lines, signaling devicesfor said link circuits, a selector switch for each of said link circuits ton actuating said signaling devices upon the arrival of said switch at a predetermined position thereof, a plurality of selector switches serving all of said link circuits, and subscriber controlled means for actuating all of said switches and causing said second selector switches to advance said first selector'switcli to said predetermined position.

5. In a telephone exchange system, a plurality of lines terminating at a central office,

a plurality of link circuits thereatffor interconnecting said lines, signaling (IBVICESIEOI' said link circuits, a multi-position switch for each of said link circuits adapted to et-v fect the actuation of said signaling devices upon the arrival of said switch at a predetermined position thereof, time regulated means for advancing said switch to said predetermined position, and operator controlled means for advancing said switch from sald predetermined position to its normal position.

6. In a telephone exchange system, a plurality of lines terminating at a central ofiice,

a plurality of link circuits thereat for. inter- 1 connecting said lines, signaling devices for said link circuits, a multi-position switch for each of saidlinkcircuits adapted to eiiect the actuation of said signaling devices upon the arrival of said switch at a predetermined position thereof, time regulated means for advancing said switch to said predetermined position, and a key common to allot said link circuits for advancmg said switch from said redetermined osition to its normal posig P p 1 end of said link circuit, a flashing control cirtion.

7. In a telephone exchange system, plu

rality of lines terminating at a central oflice, a plurality of link circu ts thereat for 1111381? connecting said lines, signaling devices. for said link circuits, t'ming means, a m ult1- position switch for each of said link c1rcu1ts having first and second predetermined po sitions, said first position be1ng a lockmg position for said timing means and sald second position being an operatlng posltion for said signaling devices, and. subscriber controlled means for moving said swltch from its normal position-and placing it under the control of said timing means to advance 1t through said first predetermined position to said second predetermined position. I

8. In a telephone exchange system, a plurality of lines terminating at a central otlice, a plurality of link circuits thereat for interconnecting said lines, signalingdevices for tionswitch for; each of said link circuits having first and second predetermined positions,

said first position being a locking position for said timing means and said second position being an operating position for said signaling devices, .means for moving said switch from its normal position and placing it under the control of said timing means to advance it through said firstpredetermined position to said second predetermined position and oper ator controlled means for advancing said switch from said second predetermined position to normal position. I

9. In a telephone exchange system, calling and called subscribers lines, a link circuit for interconnecting said lines, signaling devices for said link circuit, a plurality of time reg ulated selector switches, and means controlled jointly bythe operator and a called subscriber on a connected line for actuating said selector switches to cause the distinctive operation of said signaling devices a prede-fl termine'd period of time subsequent tothe response of the called subscriber on a connected line. g I f 10. In a telephone exchange system, calling and called subscribers lines,a link circuit ing and called subscribers lines, a link circuit for interconnectlng said lines'havlng answering and calling ends, a signal lamp for each cuit for said signaling lamps, a multi-position switch forsaid link circuit having a predetermined position thereof associated with said flashing control circuit, means initially'controlled by the respons'e of a called subscriber on a connected line for actuating to the response of'jsaid called subscriber'fo'r' advancing said switch to said predetermined position and associating said flashing control circuit with said signaling lamps. y

said link circuits, timing means, a multi-posi llfi saidswitc'h, and means effective subsequent,-

' telephone a ge system, call ing and called subscribers lines, a link circuit for interconnecting said lines having answer-j,

ing and calling ends, a signaling device for ment including a multi-pos'ition switch, for;

' said link circuit adapted to effect the actua' 1 each end of sa'idlink circuit, timing equip} relay, and a locking circuit for said second relay established subsequent to a predetermined period of operation of said timing equipment and prior 'to the arrival of said switch at said predetermined position.

13. In a telephone system, a calling subscribers line, a called subscribers line, a link circuit interconnecting said lines, signaling devices associated with said link circuit, and a plurality of selector switches actuated upon the response of a subscriber on said called subscribers line for actuating said signaling devices a predetermined period of time subsequent to said response.

14. In a telephone system, a calling subscribers line, a called subscribers line, a link circuit interconnecting said lines, signaling devices associated with said link circuit, a subscriber controlled relay in said link circuit, a second relay actuated in response to the operation of said subscriber controlled relay, anda plurality of selector switches actuated upon the operation of said second relay to effect a locking circuit for said second relay and the distinctive actuation of said signaling devices. I

15. In a telephone system, a plurality of lines terminatingat a central oflice, a link circuit thereat for interconnecting said lines,

signaling devices for said link circuit, and

timing means including a plurality of multiposition switches initially controlled by a subscriber on one of said lines, and subsequently controlled independently of said subscriber for actuating said'signaling devices upon the arrival of said switches at predetermined positions thereof.

16. In a telephone system, a calling station, a called station, a link circuit interconnecting said stations, signaling devices for said link circuits, a first selector switch, a second selector switch, means controlled by the response of a called subscriber to a call for simultaneously actuating said first and second selector switches, and means intermediate said first and second selector switches for translating the movements of said first selector switch to said second selector switch in a certain predetermined manner to cause said si naling devices to be actuated a predetermined period of time after the response of the called subscriber.

17 Timing means comprising in combination, means for producing electrical pulses periodically, registering means operable by said electrical pulses, means for connecting said registering means to said pulse source for operation thereby, signaling means controlled by said registering means and operable thereby after registration of a predetermined number of pulses.

18. Timing means comprising in combina tion, means for producing electrical pulses periodically, registering means operable by saidelectrical pulses, means for connecting said registering means to said pulse source for operation thereby, signaling means associated with said registering means and operable thereby after a fixed number of operations of said registering means.

19. Timing means comprising in combination, means for producing electrical pulses periodically, registering means operable by said electrical pulses, means for connecting said registering means to said pulse source for operation thereby, signaling means associated with said registering means and operable thereby after a fixed number of operations of said registering means, means for extinguishing said signaling means and starting anew the operation of said registering means.

20. Timing means comprising in combination, means for producing electrical pulses periodically, registering means for registering the number of said pulses up to a fixed limit, means for normally maintaining said registering means in a non-registering condition, means for connecting said registering means to said pulse source for operation thereby, signaling means associated with said registering means and operable thereby upon registration of said limiting number of pulses.

21. Timing means comprising in combination, means for producing electrical pulses periodically, registering means for registering the number of said pulses up to a fixed limit, means for normally maintaining said registering means in a non-registering condition, means for connecting said registering means to said pulse source for operation thereby, signaling means associated with said registering means and operable thereby upon registration of said limiting number of pulses, means for extinguishing sait signaling means and for restoring said registering means to the non-registering condition for starting anew the registering of said pulses.

In witness whereof, we hereunto subscribe our names this 7th day of May, 1928.

ALFRED E. HAGUE. GEORGE H. PETERSON.

Cit 

